THE CORROSION OF IRON 83 



As pointed out in the third of these articles, Dunstan in 

 particular has called attention to the manner in which various 

 agents inhibit rusting, and has sought to show that the con- 

 clusions arrived at by Moody and Friend are invalidated by 

 their having used such substances in their experiments. 



It has been shown by Friend that the inhibiting effect of 

 alkalies is due, in all probability, to the retention of a certain 

 amount of alkali at the surface of the metal ; this appears to 

 be in some degree porous, so that the alkali can be removed 

 only by long-continued washing — a precaution which Friend 

 adopted in his ingeniously simple experiments referred to in the 

 first of these articles. 



The wonderful efficiency of the film formed on slightly 

 heated steel in protecting it against corrosion is well known. 

 Next in protective efficiency comes that which is formed when 

 the metal is rendered passive in nitric acid. But other oxi- 

 dising agents appear to act only so long as they are in contact 

 with the metal ; I have often had occasion to observe of late 

 that they cease to be effective very soon after the iron is 

 withdrawn from their influence. 



It is to be regretted that Mr. Lambert did not take advice 

 before continuing his experiments, particularly before publishing 

 the account of his further work : had he taken the opinion 

 of those who have given special consideration to such matters, 

 he would probably have carried out the inquiry, if not in a more 

 effective manner, at least more circumspectly, so that the time 

 spent would not have been largely wasted in asking questions 

 in such a way that the answers are of little avail. The possible 

 flaws in his arguments would have been indicated. 



Subjects so intricate need to be dealt with comprehen- 

 sively, in the light of a mature experience; and the inquirer 

 should ever be mindful of the pitfalls which threaten each step 

 he takes. 



At present, instead of seeking counsel of one another, we too 

 often affect secrecy and resent all criticism. 



Individualism is undoubtedly the very breath of science, 

 but it now needs to be tempered judiciously with collectivism. 

 Our present failure to discuss and dispute is largely the cause 

 of the absence of understanding which now overshadows 

 scientific workers. 



